Tire manufacturing apparatus

ABSTRACT

A tire manufacturing apparatus capable of precisely mounting an annular tread on a base tire with the width center of the base tire aligned accurately with the width center of the annular tread without causing the tread to wave or the tread edges to turn up or deform. The tire manufacturing apparatus includes a drum to which a base tire is secured, a plurality of holding means extending in the width direction of the annular tread for holding the inner periphery of the annular tread, and a detecting means for detecting the amount of displacement of the annular tread relative to a predetermined position of each of the holding means. The holding means are each provided with a conveying means for moving the position of the annular tread held by the holding means. Each of the conveying means positions the annular tread at the predetermined position of each of the holding means based on the amount of displacement detected by the detecting means.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2010/071647 filed Dec. 3, 2010, claiming priority based onJapanese Patent Application No. 2010-008514 filed Jan. 18, 2010, thecontents of all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a tire manufacturing apparatus and, inparticular, to a tire manufacturing apparatus for mounting a treadhaving been formed in an annular shape on a base tire.

BACKGROUND ART

An apparatus for mounting a tread on the outer periphery of abase tireis known among tire manufacturing apparatuses. On this apparatus, aseparately manufactured base tire, which serves as the base of a tire,and an annular tread, which has been cured in advance, are joinedtogether as they are brought closer to each other by a plurality ofunits holding them separately.

-   -   Specifically, such a tire manufacturing apparatus consists of a        drum shaft, a rim assembly, a tread expanding means, a tread        pressing unit, and a moving mechanism. The drum shaft, extending        horizontally from the machine body, rotates as it is driven by a        motor. The rim assembly provided on the drum shaft holds a base        tire in such a manner as to allow air to be injected into the        base tire. The tread expanding means has a plurality of bar        members (fingers) for simultaneous expansion or contraction, the        bar members, which have a plurality of rollers protruding and        disposed in two upper and lower rows, arranged at equal        distances on a circumference. And the moving mechanism moves the        tread expanding means and the tread holder toward the rim        assembly. On this apparatus, an annular tread is first held on        the plurality of bar members such that the inner periphery of        the annular tread is radially expanded, and a base tire is        secured to the rim assembly. Then the tread radially expanded by        the tread expanding means is moved to a predetermined position        relative to the base tire, and then the tread is brought closer        as the bar members come in contact with the outer periphery of        the base tire. Finally the tread is held down to the base tire        by the tread pressing unit and then the bar members are pulled        out, thus accomplishing the integration of a base tire and a        tread.

Also, another tire manufacturing apparatus is of such a structure thatthe bar members are advanced and retracted individually. Since the barmembers can be freely advanced or retracted relative to the supportmember supporting the bar members, pulling the bar members out frombetween the base tire and the tread will accomplish the integration of abase tire and a tread.

Further, its tread expanding unit is provided with a sensor to controlthe advance and retraction of the bar members. And when the tread isplaced on the bar members, both the edge portions of the tread aredetected as they pass along the sensor, and the width center of thetread is calculated therefrom. Then the positions at which the tread isheld on the respective bar members are detected. Now the bar members areadvanced or retracted individually according to these detections so thatthe edge of the tread comes in contact with a positioning memberprovided at a predetermined position on each bar member. Thus the treadis aligned with respect to the tread expanding unit.

However, in the former case, the tread radially expanded by the treadexpanding means may not often be mounted on the base tire in a correctlyaligned condition. Therefore, there may be cases where the tread isdefectively mounted on the base tire with waves in the width directionor in an oblique orientation. Also, in the latter case, the tread may beheld aligned on the bar members of the tread expanding unit, but thealignment of the tread is accomplished with the edges of the treadbrought into contact with the positioning members. When, for example,the tread is a wing type, that is, when both edges of the tread aremolded thin-walled, the thin tread edges tend to get turned up ordeformed when they are brought into contact with the positioningmembers. Thus, when the tread is mounted on the base tire, the turned-upor deformed portions, which remain on the tread on the base tire, mayaffect the tire performance negatively. Furthermore, in both the formerand latter cases, the bar members are pulled out with the tread pressingunit holding down the annular tread to the base tire. This may cause afriction between the annular tread and the bar members and thus lead toa defective mounting of the tread on the base tire with waves in thewidth direction

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: Japanese Unexamined Patent Application    Publication No. 50-158676-   Patent Document 2: U.S. Pat. No. 4,036,677-   Patent Document 3: U.S. Pat. No. 6,521,071 B2

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

The present invention has been made to solve the foregoing problems, andan object thereof is to provide a tire manufacturing apparatus capableof precisely mounting an annular tread on a base tire with the widthcenter of the base tire aligned accurately with the width center of theannular tread without causing the tread to wave or the tread edges toturn up or deform.

Means for Solving the Problem

A first aspect of the present invention provides a tire manufacturingapparatus for mounting an annular tread on the outer periphery of a basetire. The apparatus includes a drum to which a base tire is secured, aplurality of holding means extending in the width direction of theannular tread for holding the inner periphery of the annular tread, anda detecting means for detecting the amount of displacement of theannular tread held by the plurality of holding means relative to thepredetermined position of each of the holding means. The holding meansare each provided with a conveying means for moving the position of theannular tread held by the holding means. And each of the conveying meanspositions the annular tread at the predetermined position of each of theholding means based on the amount of displacement detected by thedetecting means. According to this invention, the operator is simplyrequired to place an annular tread on the plurality of holding means,and the annular tread will be automatically located at a predeterminedposition on each holding means. Therefore, defective mounting of theannular tread with waves in the width direction can be prevented. Also,simply aligning the width center of the annular tread with the widthcenter of the base tire in any region assures precise alignment of thewidth center of the base tire with the width center of the annulartread.

A second aspect of the present invention provides a tire manufacturingapparatus for which the predetermined position may be the centerposition in the extension direction of the holding means. According tothis invention, the annular tread can be held symmetrically with respectto the holding means. Therefore, the annular tread, even when it is awide type, can be held with certainty. Moreover, aligning the extensiondirection center of the holding means with the width center of the basetire can align the width center of the base tire with the width centerof the annular tread.

A third aspect of the present invention provides a tire manufacturingapparatus for which the plurality of holding means may be disposed on aconcentric circle with the center thereof being the central axis of thedrum and the conveying means may be a conveyor belt set along theextension direction of the holding means. According to this invention,the tread is held on conveyor belts. Thus, the annular tread, even whenit is of thin edges, can be moved on the holding means withoutdeformation and mounted on the base tire without developing turned-up ordeformed tread edges.

A fourth aspect of the present invention provides a tire manufacturingapparatus for which the detecting means may be an image pickup means.According to this invention, the image pickup means constituting thedetecting means may detect the predetermined position whether it is acolor marking painted around the annular tread or a three-dimensionaltread pattern.

A fifth aspect of the present invention provides a tire manufacturingapparatus which may further include an expanding means for moving theplurality of holding means in the radial direction of the drum.According to this invention, the annular tread can be expandedcircumferentially by the plurality of holding means to a diameter largerthan the diameter of the periphery of the base tire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall schematic illustration of a tire manufacturingapparatus in accordance with the present invention.

FIG. 2 is a side view and a plan view of a base tire holding unit inaccordance with the present invention.

FIG. 3. is a side view and an elevational view of a tread expanding unitin accordance with the present invention.

FIG. 4 is a side view and a plan view of a holding means in accordancewith the present invention.

FIG. 5 is a top view showing a placement of a tread width centerdetecting means relative to a conveying means in accordance with thepresent invention.

FIG. 6 is a block diagram of a control unit in accordance with thepresent invention.

FIG. 7 is a flowchart showing a procedure for mounting an annular treadon a base tire in accordance with the present invention.

Hereinafter, the invention will be described based on preferredembodiments which do not intend to limit the scope of the claims of thepresent invention but exemplify the invention. All of the features andthe combinations thereof described in the embodiments are notnecessarily essential to the invention, and they include constructionsand arrangements to be employed selectively.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a description will be given of a tire manufacturingapparatus 1 according to the present invention.

FIG. 1 is an overall schematic illustration of the tire manufacturingapparatus 1. As shown, the tire manufacturing apparatus 1 roughlyconsists of a base tire holding unit 2 for holding a base tire 10, atread expanding unit 3 for radially expanding an annular tread(hereinafter referred to as “tread”) 11 which has been cured and moldedin advance with its internal diameter smaller than the external diameterof the base tire 10, a pressing unit 4 for pressing the surface of thetread 11 mounted on the base tire, and a control unit 5 for controllingthe mounting of the tread 11 onto the base tire 10. All these units areinstalled on a base 6 having the installation surface formedhorizontally. These units 2 to 5 will be explained one by one below.Note that although the annular tread has been described above as havingan inner diameter smaller than the external diameter of the base tire,the annular tread may have an inner diameter equal to or larger than theexternal diameter of the base tire.

FIG. 2A is a side view of a base tire holding unit 2, and FIG. 2B is aplan view of the base tire holding unit 2.

The base tire holding unit 2 includes a holding unit body 21, a drumshaft 22 extending horizontally from the inside to the outside of theholding unit body 21, a drum motor 24 to cause the rotation of the drumshaft 22, a compressor 25 installed inside the holding unit body 21, adrum 23 fixed to an end of the drum shaft 22, and a base tire centerdetecting means 26 consisting of a CCD camera 27 and a light castingunit 28. The holding unit body 21, which is mounted on one side in thelongitudinal direction E of the base 6, has the drum shaft 22penetrating it in the longitudinal direction E. The drum shaft 22 isrotatably supported by not-shown bearings which are fixed to the holdingunit body 21. The drum 23 is attached to one end of the drum shaft 22,and a pulley 29 to the other end thereof.

The drum 23, which is a cylindrically-formed wheel, is made up of aplurality of drum pieces which are the radially divided pieces of thewheel. It is provided with an expansion mechanism capable of radiallyexpanding or contracting the drum pieces in correspondence to a varietyof tire sizes. In a preferred expansion mechanism, the drum pieces aremoved radially with air supplied into or discharged from not-shown aircylinders attached to the drum pieces. The drum 23, fitted along theinner periphery 10 a of the base tire 10, holds the base tire 10rotatably. Also, mounted on the peripheral surface 23 a of the drum 23is a seal ring 34, which constitutes an internal pressure holding means32. The seal ring 34, which maybe a belt-like rubber or like materialformed into a cylinder, is attached firmly to the drum 23, wrappingaround the peripheral surface 23 a thereof. Further, the seal ring 34 isprovided with a valve 35 which penetrates it in the thickness direction.Thus, when the drum 23 is expanded radially, the inner periphery 10 a ofthe base tire 10 remains in close contact with the seal ring 34, withthe seal ring 34 stretched in such a manner as to cover the gaps betweenthe drum pieces. This creates a closed space inside the base tire 10sealed by the seal ring 34, thereby preventing the leaks of air suppliedinto the base tire 10 through the valve 35.

The drum motor 24 may be a geared motor having a reduction mechanismtherewithin, and the rotative force of the motor is outputted in adecelerated state. A pulley 36 is attached to the rotation output shaft24 a of the drum motor 24. A belt 38 is set on the pulley 36 and thepulley 29 fixed to the drum shaft 22, and the rotation of the drum motor24 is communicated to the drum shaft 22 by way of the belt 38.

The base tire center detecting means 26, which consists of a CCD camera27 and a light casting unit 28, is secured to an end of a support arm 39extending from the top surface of the holding unit body 21. The CCDcamera 27 is anchored such that the imaging center coincides with thewidth center W1 of the drum 23, whereas the light casting unit 28 isanchored to the support arm 39 at a predetermined angle so that a slitlight cast therefrom extends in a width direction of the drum 23. Thewidth of the slit light cast from the light casting unit 28 is so set asto be wider than the width of the base tire. And the control unit 5 tobe discussed later detects the width W of the base tire 10 from theimage outputted from the CCD camera 27 and further detects the positionof the width center W2 of the base tire 10 based on the width W.

The pressing unit 4, called the stitcher roller, is disposed in aposition opposite to the periphery of the base tire 10 mounted on thedrum 23. As shown in FIG. 2B, the pressing unit 4 includes a frame 41installed upright on the base 6, a pair of arms 42, 42 projecting inopposition to the periphery of the base tire 10 from a side of the frame41, and a roller 43 held rotatably by the arms 42, 42. The arms 42, 42projecting from the frame 41, facing the periphery of the base tire 10,are moved in the width direction and the radial direction of the basetire 10 by not-shown drive mechanism. The roller 43, rotatably held bythe arms 42, rotates as it comes in contact with the surface of thetread 11 mounted on the base tire 10, and presses the tread 11 againstthe base tire 10, thereby removing its distortions when the tread 11 isfirst applied to the base tire 10.

FIG. 3A is a side view of a tread expanding unit 3, and FIG. 3B is anelevational view of the tread expanding unit 3.

Between the drum 23 of the base tire holding unit 2 and the treadexpanding unit 3, a pair of rails 8, 8 is laid on the base 6 in parallelwith the central axis A of rotation of the drum shaft 22. The treadexpanding unit 3 is disposed on a pedestal 9 with wheels 9 a which aremovable toward or away from the drum 23 on the rails 8, 8. The treadexpanding unit 3 includes an expanding unit body 45, expanding means 46,holding means 47, a tread width center detecting means 48, and a movingmeans 49. The expanding unit body 45 is made up principally of a mainspindle 51, a circular plate 52, and a tread rotating motor 53. The mainspindle 51, which is a shaft member extending horizontally from theinside to the outside of the expanding unit body 45, is supported bynot-shown bearings provided within the expanding unit body 45 such thatthe central axis B thereof is coaxial with the central axis A of thedrum shaft 22. In other words, the central axis B of the tread expandingunit 3 is aligned with the central axis A of the drum shaft 22 of thebase tire holding unit 2.

The circular plate 52 is attached to the end of the main spindle 51extending toward the base tire holding unit 2. The circular plate 52,which is disc-shaped, has a flat mounting surface 54 a in opposition tothe drum 23 and a flange surface 54 b connected to the main spindle 51.The circular plate 52 is so formed that the diameter thereof is largerthan that of the tread 11 to be mounted. The mounting surface 54 a andthe flange surface 54 b are formed as planes parallel to each other, andthe flange surface 54 b is coupled to the main spindle 51 in such amanner that the central axis B of the main spindle 51 is orthogonalthereto. A pulley 61 is attached to the middle part of the main spindle51 within the expanding unit body 45. The tread rotating motor 53 forrotating the main spindle 51 is installed within the expanding unit body45 and anchored to the pedestal 9. A pulley 62 is attached to therotation output shaft of the tread rotating motor 53. A belt 63 is seton the pulley 61 and the pulley 62, and the rotative force of the treadrotating motor 53 is communicated to the main spindle 51 by way of thebelt 63. Also, a rotational angle sensor 65 for detecting the rotationalangle of the circular plate 52 is attached to the other end of the mainspindle 51 and outputs the rotational angle detected to the control unit5 to be discussed later.

A plurality of expanding means 46 are mounted on the mounting surface 54a of the circular plate 52.

The expanding means 46 are each comprised of a linear rail 57 and aslider 58 which slides on the linear rail 57. The linear rails 57, whichare rail members extending radially from the center of the mountingsurface 54 a, are installed at even intervals circumferentially on thecircular plate 52. The linear rail 57 has a rotating bolt extending inits extension direction, and the slider 58 has a nut associated with therotating bolt. These rotating bolt and nut constitute a bolt and nutmechanism. Thus, rotation of the rotating bolt driven by a servo motor66, which is mounted on an end of the linear rail 57, can cause theslider 58 to slide along the linear rail 57 in a radial direction of thecircular plate 52. In the present embodiment, there are 10 sets of alinear rail 57 and a slider 58 which constitute the expanding means, butit should be understood by those skilled in the art that the number isnot limited to 10 sets and may be 8 set, 12 sets and so on. Also,although the expanding means are constructed of linear rails 57 in thisembodiment, they may be constructed of a linkage mechanism or the like.Also, a holding means 47 is attached to each of the sliders 58.

FIG. 4A is a side view of a holding means 47, and FIG. 4B is a plan viewof the holding means 47.

As shown in FIGS. 4A and 4B, the holding means 47 includes a finger 55anchored at one end to the slider 58 and extending toward the drum 23,as if jutting out from the mounting surface 53 a of the circular plate52, and a conveyor belt 73 as a conveying means stretched in theextension direction of the finger 55. The finger 55 consists of a pairof long frame plates 71, 71 extending horizontally from the slider 58toward the drum 23 and a plurality of timing wheels 72 rotatablysupported between the long frame plates 71, 71 at predeterminedintervals along the extension direction thereof. The long frame plates71, 71, which are formed with a length sufficiently longer than thewidth of the tread 11 to be mounted, have a plurality of bearing holes71 a to support the revolving shafts 72 a of the plurality of timingwheels 72. Of the bearing holes 71 a, the bearing hole 71 a closest tothe drum 23 is located such that part of the timing wheel 72 placedthere is exposed from the end of the long frame plates 71, 71. Also, thecenters of the bearing holes 71 a are located offset to one side fromthe center line H of the width (finger thickness) of the long frameplates 71, 71, such that part of the timing wheels 72 set in place isexposed above the top side of the long frame plates 71, 71.

The timing wheels 72 turn around the revolving shafts 72 a supported bythe bearing holes 71 a. And a servo motor 74 is directly connected tothe revolving shaft 72 a of the timing wheel 72 located closest to theslider 58. The outer periphery 72 b of each timing wheel 72 is indentedalong the circumference thereof.

A conveyor belt 73 as a conveying means is set on the plurality oftiming wheels 72. With the conveyor belt 73 set on the plurality oftiming wheels 72, the top surface 73A of the conveyor belt 73 whichcomes in contact with the inner periphery of the tread 11 is locatedabove the top side of the long frame plates 71, 71 and also exposed onthe side closer to the drum 23 from the end of the long frame plates 71,71. Therefore, as shown in FIG. 1, driven by the normal or reverserotation of the servo motor 74, the tread 11 set on the plurality offingers 55 can be moved on the conveyor belt 73 in the direction closerto or further from the drum 23 without touching the long frame plates71, 71. Also, since the long frame plates 71, 71 of the finger 55 arefixed to the slider 58, the tread 11 set on the plurality of fingers 55can be expanded or contracted as the plurality of sliders 58 are movedin the normal direction N along the linear rails 57 on the circular face56 of the circular plate.

FIG. 5 is a top view showing a placement of a tread width centerdetecting means 48 relative to a conveying means.

The tread width center detecting means 48 consists of a CCD camera 75and a light casting unit 76, for instance. As shown in FIG. 3A, the CCDcamera 75 and the light casting unit 76 are mounted on the end of an arm77 extending horizontally from the expanding unit body 45. The CCDcamera 75 is located such that the imaging center W5 coincides with theextension direction center W3 of the finger 55. Also, the light castingunit 76 casts a strip light, which is parallel to the extensiondirection of the finger 55, for a range wider than the maximum width MWof the tread 11 that can be supported by the fingers 55, from under theCCD camera 75.

Thus arranged, the tread width center detecting means 48 captures animage of the strip light cast in the width direction of the tread 11 seton the fingers 55 and outputs the captured image to the control unit 5to be discussed later. This is for the control unit 5 to detect thesurface feature or colored line, e.g., a white line, present at thewidth center W4 of the tread 11 and continuing circumferentially aroundthe tread 11. In this embodiment, the tread width center detecting means48 is comprised of a CCD camera 75 and a light casting unit 76, but thearrangement is not limited thereto. For example, when the width centerW4 to be detected is in a part of a three-dimensional tread pattern, thewidth cross section of the tread 11 may be detected by a two-dimensionalshape sensor, and the width center W4 of the tread 11 may be detectedfrom the width cross section.

The moving means 49 consists of an actuator which has a servo motortherewithin. With the rotation of the servo motor, a piston 49 badvances from or retracts back to a cylinder 49 a. The moving means isconstructed such that the cylinder 49 a is anchored to the base 6 andthe piston 49 b is attached to a pushing plate 9 b which is secured tothe front end of the pedestal 9. The piston 49 b is advanced orretracted according to the advance or retract signal from the controlunit 5 to be discussed later, thereby getting the tread expanding unit 3to approach or separate from the drum 23 of the base tire holding unit2.

FIG. 6 shows a block diagram and electrical connection of a control unit5.

The control unit 5, which includes a storage 15, a controller 16, and anarithmetic processor 17, controls the mounting of the tread 11 to thebase tire 10. Coupled to the control unit 5 are an operation panel, aircylinders as the expanding mechanism for the drum 23, a compressor 25 asthe internal pressure holding means 32, a drum motor 24, a treadrotating motor 53 of the tread expanding unit 3, servo motors 66 of theexpanding means 46, servo motors 74 of the holding means 47, arotational angle sensor 65, a CCD camera 27 and a light casting unit 28of the base tire center detecting means 26, a CCD camera 75 and a lightcasting unit 76 of the tread width center detecting means 48, a movingmeans 49 for moving the tread expanding unit 3 toward or away from thebase tire holding unit 2, and a pressing unit 4 for evenly press thetread 11 mounted on the base tire 10.

The storage 15 stores information on the types and sizes of the tread11, the structures and sizes of the base tire, and the patterns ofcombination of tread 11 and base tire 10 in advance. The controller 16controls the overall aspects of mounting the tread 11 on the base tire10.

The arithmetic processor 17 determines the amount of displacement of thewidth center W4 of the tread 11 from the width center W2 of the basetire 10 detected by the base tire center detecting means 26 andcalculates the amount of shift to be made by the moving means 49 to havethe width center W2 of the base tire 10 aligned with the width center W4of the tread 11. Also, the arithmetic processor 17 calculates therotating speed of the conveyor belts 73 when the tread 11 is mountedonto the base tire 10 according to the speed at which the treadexpanding unit 3 is moved away from the base tire holding unit 2.

The operation panel to be coupled to the controller 16 is a touch paneltype or the like capable of selectively inputting information on thetread 11 to be mounted and the base tire 10. The information on thetread 11 and the base tire 10 is to be inputted by an operator.

Based on the information on the base tire 10 inputted from the operationpanel, the controller 16 outputs a holding signal to the air cylinder,which is the expansion and contraction mechanism for the drum 23, inresponse to the size of the base tire 10, thereby causing the expansionor contraction of the drum 23 to fit the inner diameter of the base tire10.

Also, the controller 16 outputs an internal pressure supply signal tothe internal pressure holding means 32 to supply air from the compressor25 so as to keep a predetermined internal pressure inside the base tire10 that is secured to the drum 23.

Also, the controller 16 outputs to the CCD camera 27 of the base tirecenter detecting means 26 a zero point detection signal to detect thewidth center W1 of the drum 23 before the base tire 10 is set on thedrum 23 and a base tire width center detection signal to start an imagepickup to detect the width center W2 of the base tire 10 held on thedrum 23. And as the drum 23 starts rotating at a rotation start signalfrom the controller 16 to the drum motor 24, the captured images startbeing outputted from the CCD camera 27 to the control unit 5.

Also, the controller 16 outputs a tread rotation signal to the treadrotating motor 53. As the tread rotating motor 53 rotates in response tothe tread rotation signal, the tread 11 set on the plurality of fingers55 rotates circumferentially, and the amount of displacement between theextension direction center W3 of the fingers 55 and the width center W4of the tread 11 is detected by the tread width center detecting means48.

Also, the controller 16 outputs a tread width center detection signal tothe CCD camera 75 of the tread width center detecting means 48 to startan image pickup simultaneously with its outputting a tread rotationsignal to the tread rotating motor 53. And the CCD camera startscapturing images in response to the signal and outputs captured imagesto the control unit 5.

Also, the controller 16 outputs an expansion signal or a contractionsignal to the servo motors 66 for the plurality of sliders 58. With anexpansion signal outputted to the servo motors 66, the fingers 55 movegradually outward in the radial direction of the circular face 56 untilthe diameter of the tread 11 set on the plurality of fingers 55 becomeslarger than the diameter of the base tire 10. On the other hand, with acontraction signal outputted to the servomotors 66, the fingers 55 movegradually inward in the radial direction of the circular face 56 untilthe diameter of the tread 11 set on the plurality of fingers 55 shrinksfrom the expanded diameter to the diameter close to that of the drum 23.It is to be noted that the contraction signal is one to be outputtedwhen the width center W2 of the base tire 10 reaches an alignment withthe width center W4 of the tread 11.

Also, the controller 16 outputs a centering signal and a mounting signalto the servo motors 74 to drive the conveyor belts 73 of the fingers 55of the tread expanding unit 3. The centering signal, which is a signaloutputted individually to the plurality of servo motors 74, is given toadjust the width center W4 of the tread 11 set on the fingers 55 to theextension direction center W3 of the finger 55. That is, with acentering signal outputted, the inner periphery of the tread 11 incontact with the top surface 73A of the conveyor belt 73 is adjusted inthe drive direction (closer to or further from the drum 23) of theconveyor belt 73. And when the adjustment operations with all the servomotors 74 are completed, the tread 11 is set in an identical position onall the fingers 55. The mounting signal, which is a signal outputtedcollectively to the plurality of servo motors 74, is given to convey, ortransfer, the tread 11 in the same attitude, or position, as it is seton the fingers 55 after the adjustment operations. The mounting signalis outputted when the tread 11 is placed in such a position that thewidth center W2 of the base tire 10 is aligned with the width center W4of the tread 11. And based on this signal, the tread 11 is conveyed outof the conveyor belts 73 of the fingers 55 to be placed on the outerperiphery of the base tire 10.

Also, the controller 16 outputs a positioning signal, a separationsignal, and a standby signal to the moving means 49. The positioningsignal is a signal to bring the tread expanding unit 3, that is, thetread 11, closer to the drum 23 of the base tire holding unit 2. Withthis signal outputted, the tread expanding unit 3 is moved closer to thedrum 23 on the rails 8. The separation signal is a signal outputted whenthe tread 11 is to be placed on the outer periphery of the drum 23 afterthe tread expanding unit 3 is moved to a predetermined position(placement position). With this signal outputted, the tread expandingunit 3 is moved in a separating direction from the drum 23 on the rails8.

Also, the controller 16 outputs a conditioning signal to the pressingunit 4. The conditioning signal is a signal to move the roller 43 of thepressing unit 4 to the tread 11 mounted on the base tire 10 and pressthe tread 11 with the roller 43 in such a manner as to fix it to thebase tire 10.

Also, inputted to the controller 5 are images captured by the base tirecenter detecting means 26 and images captured by the tread width centerdetecting means 48. Further, inputted thereto are the angles of thefingers captured by the tread width center detecting means 48 from therotational angle sensor 65.

FIG. 7 is a flowchart showing a procedure for mounting a tread 11 on abase tire 10 using a tire manufacturing apparatus 1 of the presentinvention.

As shown in FIG. 7, in the mounting of a tread 11 on a base tire 10, thebase tire 10 is first placed on the periphery of a drum 23, and thetread 11 is set on a plurality of fingers 55.

Next, information on the tire size of the base tire 10 and the type ofthe tread 11 is inputted from an operation panel. A control unit 5outputs to the drum 23 an internal pressure supply signal to supply aircollected in a compressor 25 to the base tire 10 by expanding the drum23, thereby securing the base tire 10 to the drum 23.

Next, the drum 23 is rotated, and the images of the surface of the basetire 10 are captured continuously by a CCD camera 27 to make certainthat the base tire 10 is so set that the width center W2 thereof isorthogonal to the central axis A of the drum 23 throughout thecircumference of the base tire 10. If the base tire 10 is not set withthe width center W2 thereof orthogonal to the central axis A of thedrum. 23 throughout the circumference thereof, then the base tire 10must be reset on the drum. 23. When the base tire 10 is so set that thewidth center W2 thereof is orthogonal to the central axis A of the drum23 throughout the circumference of the base tire 10, the data on thewidth center W2 of the base tire 10 is stored.

On the other hand, the tread 11 set on the fingers 55 of the treadexpanding unit 3 is expanded, with all the sliders 58 simultaneouslymoving radially outward, until the diameter of the tread 11 becomeslarger than the outside diameter of the base tire 10, in response to anexpansion signal from the control unit 5.

Next, the control unit 5 outputs a tread rotation signal to a treadrotating motor 53 to rotate a circular plate 52 and further outputs atread width center detection signal to a CCD camera 75 to capture theimages of the surface of the rotating tread 11. Based on the imagescaptured and outputted by the CCD camera 75, the control unit 5 detectsa position on the tread 11 serving as a marker, that is, the widthcenter W4 of the tread 11 and calculates the amount of displacementbetween the width center W4 and the extension direction center W3 ofeach finger 55. Further, the control unit 5 stores the amount ofdisplacement by associating it with the angle of the drum 23 detected bya rotational angle sensor 65 when the amount of displacement isdetected. And the control unit 5 causes the servo motor 74 of the finger55 located at the angle associated with the amount of displacement torun and rotate the conveyor belt 73. In this manner, the control unit 5controls the conveyor belts 73 of all the fingers 55 so that the widthcenter W4 of the tread 11 is located at the extension direction centerW3 of the finger 55. As a result, the tread 11 is held in alignment withthe extension direction center W3 of the fingers 55.

Through the above-described process, the setting of the base tire 10 onthe drum 23 and the holding of the tread 11 on the fingers 55 arecompleted. Then the mounting of the tread 11 on the base tire 10 isperformed through the following process.

With the tread 11 held in alignment with the fingers 55, the controlunit 5 outputs a positioning signal to a moving means 49, thereby movingthe tread expanding unit 3 closer to the drum 23 of the base tireholding unit 2 and stopping it in a position where the tread 11surrounds the periphery of the base tire set on the drum 23.

Next, the CCD camera 27 begins shooting the images to detect the amountof displacement between the width center W4 of the tread 11 and thewidth center W2 of the base tire 10 and outputs the captured images. Itis to be noted that, in actuality, the width center W4 of the tread 11only is detected since the width center W2 of the base tire 10 isalready stored as the position detected when the base tire 10 isinitially secured. From the images of the surface of the tread 11captured by the CCD camera 27, the control unit 5 detects the surfacefeature representing the width center W4 of the tread 11 and alsodetects the amount of its displacement from the already stored positionof the width center W2 of the base tire 10. Then the control unit 5adjusts the position of the tread 11 relative to the base tire 10 bydriving the moving means 49 based on the detected amount ofdisplacement, so that the width center W4 of the tread 11 is alignedwith the width center W2 of the base tire 10.

Next, as the width center W4 of the tread 11 is aligned with the widthcenter W2 of the base tire 10, the control unit 5 outputs a contractionsignal to the servo motors 66, thereby causing the sliders 58 to movetoward the center until the bottoms of the fingers 55 come in contactwith the periphery of the base tire 10.

Next, the control unit 5 outputs a separation signal to the moving means5 to have the tread expanding unit 3 back away and at the same timeoutputs a mounting signal to the servo motors 74 of the fingers 55 torotate the conveyor belts 73 at such a speed as to place the tread 11onto the periphery of the base tire 11 in correspondence to the backingspeed of the tread expanding unit 3. That is, the control unit 5 outputsa mounting signal to the servo motors 74 of the fingers 55 such that thespeed at which the tread expanding unit 3 separates itself from the drum23 is the same as the speed at which the tread 11 is conveyed by theconveyor belt 73. As a result, the tread 11 is mounted onto the basetire 10 in a relatively stationary state.

Next, when the tread 11 is placed completely over the periphery of thebase tire 10 separate from the fingers 55, the control unit 5 outputs astandby signal to the moving means 49 to move the tread expanding unit 3to a predetermined standby position.

Then the control unit 5 outputs a rotation start signal to the drummotor 24 to check for any abnormality of the base tire 10 with the tread11 mounted thereon, and further the images of the surface of the mountedtread 11 are captured circumferentially by the CCD camera 27. Using theimages captured by the CCD camera 27, the control unit 5 detects theright and left amounts of deflection of the width center W4 of the tread11 and the amount of displacement of the width center W4 of the tread 11from the width center W2 of the base tire 10 stored in advance in thecontrol unit 5. Thus, normalcy is determined if the amount of deflectionand the amount of displacement are within their predetermined limits.And when an abnormality is determined, an error is outputted to theoperation panel, and the base tire 10 with the tread 11 on should beremoved from the drum 23 and disposed of by the operator, for instance.

Next, when the mounting is determined normal, the control unit 5 outputsa conditioning signal to the pressing unit 4 to operate the roller 43 incontact with the surface of the tread. In this operation, the roller 43is traversed in the tire width direction while the tire with the treadon rotates a predetermined number of turns in order to condition thetread 11 to the base tire 10.

Through the above-described process, the mounting of the tread 11 on thebase tire 10 is completed.

As described hereinabove, according to a tire manufacturing apparatus 1of the present invention, a base tire holding unit 2 for securing a basetire 10 and a tread expanding unit 3 in a position opposite to the basetire holding unit 2 are mounted on a base 6. The tread expanding unit 3approaches the base tire holding unit 2 along the rails 8, 8 laid on thebase 6 to mount an expanded tread 11 on a base tire 10 secured to thebase tire holding unit 2, thereby accomplishing an integration of thebase tire 10 and the tread 11.

In particular, the tread expanding unit 3 is provided with a tread widthcenter detecting means 48 for detecting the width center W4 of the tread11 set on the fingers 55 thereof. As such, it is now possible to controlthe conveyor belts 73 individually so as to align the width center W4 ofthe tread 11 with the extension direction center W3 of each finger 55 ofthe tread expanding unit 3, thus aligning the tread 11 in parallel withthe circular face 56 of the circular plate 52. Therefore, the operatoronly has to set the tread 11 on the plurality of fingers 55.

Also, the tread 11 is held on the fingers 55 in alignment parallel tothe circular face 56 of the circular plate 52. Accordingly, when thetread 11 is to be mounted on the base tire 10, the width center W2 ofthe base tire 10 and the width center W4 of the tread 11 can be alignedwith each other simply by moving the tread expanding unit 3.

Further, when the tread 11 is mounted on the base tire 10, the treadexpanding unit 3 is moved in such a manner that the width center W2 ofthe base tire 10 is aligned with the width center W4 of the tread 11.And the fingers 55 are brought into contact with the base tire 10 whilemaintaining the alignment of the width center W2 of the base tire 10 andthe width center W4 of the tread 11, and then the tread expanding unit 3is separated from the base tire 3. At this time, the servo motors 74 ofthe conveyor belts 73 of all the fingers 55 are driven synchronously incorrespondence to the speed of separation. Thus the correspondencebetween the rotating speed of the conveyor belts 73 and the retractionspeed of the piston 49 b to keep the tread 11 stationary in place makesit possible to place the tread 11 from one edge to the other on theperiphery of the base tire 10.

In the embodiment described above, the tread 11 is mounted onto the basetire 10 while it is kept in a relatively stationary state. And this isaccomplished by a mounting signal outputted to the servo motors 74 ofthe fingers 55 to equalize the separation speed of the tread expandingunit 3 from the drum 23 and the tread 11 conveyance speed of theconveyor belts 73. However, the arrangement may be such that the treadexpanding unit 3 is backed up with its separation speed from the basetire holding unit 2 calculated by the control unit 5 according to therotating speed of the conveyor belts when the tread 11 is to be mountedon the base tire 10. In this manner, too, the tread 11 can be mounted onthe base tire 10 while it is kept in a relatively stationary state.

Also, the arrangement may be such that the tire manufacturing apparatus1 as described above is further provided with an inter-unit distancesensor for detecting the distance between the base tire holding unit 2and the tread expanding unit 3. In this case, the arithmetic processor17 of the control unit 5 calculates the amount of displacement betweenthe width center W2 of the base tire and the width center W1 of the drum23 as detected by the base tire center detecting means 26. Then, usingthe width center W1 of the drum 23 as the mounting origin, thearithmetic processor 17 calculates the travel distance of the treadexpanding unit 3 by adding the amount of displacement as the correctionvalue to the distance between the base tire holding unit 2 and the treadexpanding unit 3 as measured by the inter-unit distance sensor. Then thecontrol unit 5 outputs a positioning signal to the moving means 49 toalign the width center W2 of the base tire 10 with the width center W4of the tread 11. When the width center W2 of the base tire 10 is alignedwith the width center W4 of the tread 11, a separation signal may beoutputted so that the conveyor belts 73 are driven and the moving means49 are moved away from the base tire 10 at a speed corresponding to themoving speed of the conveyor belts 73.

Also, as another mode of the tread width center detecting means 48, atread width center detecting means 48 maybe provided on each of thefingers 55. Thus, the amount of displacement between the width center W4of the tread 11 and the extension direction center W3 of each finger 55maybe detected individually by the tread width center detecting means 48provided on each finger 55 which is connected to the control unit 5.Then each conveyor belt 73 may be driven in such a manner that the widthcenter W4 of the tread 11 is aligned with the extension direction centerW3 of each finger 55. In this manner, the width center W4 of the tread11 may be aligned with the extension direction center W3 of the finger55 for each of the fingers 55 without rotation of the tread 11.

In the foregoing specification, the invention has been described withreference to specific embodiments thereof. However, the technical scopeof the invention is not limited to the described scope of theembodiments. And it should be evident to those skilled in the art thatvarious modifications and changes may be made thereto without departingfrom the spirit and scope of the invention.

DESCRIPTION OF REFERENCE NUMERALS

-   1 tire manufacturing apparatus-   2 base tire holding unit-   3 tread expanding unit-   4 pressing unit-   5 control unit-   10 base tire-   11 annular tread-   15 storage-   16 controller-   17 arithmetic processor-   22 drum shaft-   23 drum-   26 base tire center detecting means-   27 CCD camera-   28 light casting unit-   46 expanding means-   47 holding means-   48 tread width center detecting means-   55 finger-   65 rotational angle sensor-   66 servo motor-   72 timing wheel-   73 conveyor belt-   74 servo motor-   75 CCD camera-   76 light casting unit-   A, B central axis-   W1, W2, W4 width center-   W3 center-   H center line

The invention claimed is:
 1. A tire manufacturing apparatus for mountingan annular tread on a base tire, the apparatus comprising: a drum towhich the base tire is secured; a plurality of motorized conveyor belts,for holding a plurality of positions on an inner periphery of theannular tread, disposed on a concentric circle with the center thereofbeing the central axis of the drum and configured to convey the annulartread by independently operating the conveyor belts in a directionparallel to the central axis of the drum; a respective motor from aplurality of motors for driving each of the plurality of conveyor belts;a control unit controlling the plurality of motors; a plurality ofholders extending along with an extending direction of the plurality ofconveyor belts for holding each of the plurality of conveyor beltsindividually; and a detector for individually detecting the amount ofdisplacement between a central position in a width direction of theannular tread held and a central position of each of the plurality ofholders in the extending direction, wherein the control unit isprogrammed to determine the center of the base tire and is alsoprogrammed to independently control each plurality of motors so as tomove the annular tread at the plurality of positions such that thecentral position in the width direction of the annular tread held byeach of the plurality of conveyor belts becomes located at the centralposition in the extending direction of each of the plurality of holders,based on the amount of displacement detected at each of the plurality ofholders.
 2. The tire manufacturing apparatus as recited in claim 1,wherein the detector includes a camera.
 3. The tire manufacturingapparatus as recited in claim 1, further comprising an expander formoving each of the plurality of holders in a radial direction,respectively, of the drum.
 4. The tire manufacturing apparatus asrecited in claim 2, further comprising an expander for moving theplurality of holders in the radial direction of the drum.